How to use relative path for compiling

Hi there,

We are currently facing a problem around compilation and `swiftc` command.

When building, xcode gives the list of files to compile to swiftc in absolute path :

CompileSwiftSources normal x86_64 com.apple.xcode.tools.swift.compiler (in target: Module)
    cd /Users/user/Documents/workspace/company/project
    export DEVELOPER_DIR=/Applications/Xcode.app/Contents/Developer
    export SDKROOT=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator12.1.sdk
    /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swiftc -incremental -module-name Module -Onone -whole-module-optimization -enforce-exclusivity=none -DDEBUG -Onone -sdk /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator12.1.sdk -target x86_64-apple-ios9.3-simulator -g -module-cache-path /Users/user/Documents/workspace/company/project/DerivedData/ModuleCache.noindex -Xfrontend -serialize-debugging-options -profile-coverage-mapping -profile-generate -enable-testing -index-store-path /Users/user/Documents/workspace/company/project/DerivedData/project/Index/DataStore -swift-version 4.2 -I /Users/user/Documents/workspace/company/project/DerivedData/project/Build/Products/development-iphonesimulator -F /Users/user/Documents/workspace/company/project/DerivedData/project/Build/Products/development-iphonesimulator -F /Users/user/Documents/workspace/company/project/Carthage/Build/iOS /Users/user/Documents/workspace/company/project/Module/File.swift /Users/user/Documents/workspace/company/project/Module/File2.swift /Users/user/Documents/workspace/company/project/Module/File3.swift

We found the `working-directory` parameter to the swiftc command and wonder how to make xcode use it, in order to reduce the command line length ?

We are currently reaching the mac os buffer limit for command line, that is 2Mb.